Apple Inc.

Tom-Davy W Saux

Vladan Bajic

Hanchi Chen

Andrew E Greenwood

Martin E Johnson

Esge Brandt Andersen

John Woodruff

Justin Derry Crosby

Baptiste Pierre Paquier

Brian D Clark

Raghavendra S Prabhu

Victoria Chiu

Scott Charles Grinker

Vasu Iyengar

Yang Lu

Tyrone T Chen

Thomas M Jensen

Jakub Mazur

Tony S Verma

Martin Kuster

Afrooz Family

Sorin V Dusan

Andrew P Bright

Robert Denton Silfvast

Dana C Massie

Thanh Phong Hua

Prateek Murgai

Disclosed are systems and methods for adaptive noise cancellation (ANC) at a virtual microphone located at the eardrum of a wearer of an earphone. The techniques estimate the level of leakiness of ambient noise in the earphone from the magnitude of the gain of the transfer function of the feed forward loop filter of the ANC. Based on the estimated leakiness, the techniques estimate the transfer function of the feed forward loop filter to compensate for the difference in the effect of noise cancellation at the virtual microphone and error microphone. A bias term that represents the difference in the frequency response of the attenuated noise at the virtual and error microphone may be added to the adaptive feed forward algorithm. The ANC operation may apply the bias term to the adaptive feed forward loop filter to reduce the ambient noise at the eardrum rather than at the error microphone.

Adaptive virtual microphone for earbuds

A method performed by an in-ear headphone. Coupled to the in-ear headphone is a first ear tip that is inserted into an ear canal of a user. The method obtains an audio signal from an audio source device paired with the in-ear headphone and uses the signal to drive a speaker of the headphone to output a sound into the ear canal. The method obtains a microphone signal that is responsive to the outputted sound. The method notifies the user to replace the first ear tip with a second ear tip in response to a parameter associated with the microphone signal being less than a threshold.

Acoustic detection of in-ear headphone fit

Signal to noise ratio, SNR, is determined in an acoustic ambient environment of an against-the-ear audio device worn by a user, wherein the acoustic ambient environment contains speech by a talker. When the SNR is above a threshold, dynamic range control is applied, as positive gain versus input level, to an audio signal from one or more microphones of the audio device. When the SNR is below the threshold, the dynamic range control applies as zero gain or negative gain to the audio signal. Other aspects are also described and claimed.

Ambient noise aware dynamic range control and variable latency for hearing personalization

Disclosed are systems and methods for performing adaptive equalization operations to reduce variations in the frequency response of audio signals at the eardrum of a wearer of an earphone. The assumption that the frequency response of the error microphone matches the frequency response at the eardrum may not be true due to signal leakage effects and the shape of the ear canal. Techniques are disclosed for the adaptive equalization operations to perform a calibration algorithm to compensate for the effects of the signal leakage and the shape of the ear canal. The earphone may estimate the transfer function from the speaker to the error microphone and may estimate the load impedance from the earphone based on a calibrated relationship between the transfer function and the load impedance. The adaptive equalization may use a calibration algorithm to adjust the frequency response at the error microphone to match that at the eardrum.

Adaptive equalization compensation for earbuds

A method performed by an in-ear headphone that includes a speaker and an internal microphone. The method receives a microphone signal from the internal microphone that indicates a current sound pressure level (SPL) in an ear canal of a user. The current SPL is a result of a control leak from the in-ear headphone into an ambient environment that reduces a SPL in the ear canal between 2 dB and 25 dB at a frequency within a frequency range than if otherwise not present. The method determines an active noise cancellation (ANC) filter based on the microphone signal and generates an anti-noise signal using the ANC filter. The method drives the speaker using the anti-noise signal to reduce the current SPL in the ear canal of the user as much as 25 dB at a frequency within the frequency range.

Feedback acoustic noise cancellation tuning

An audio system has an ambient sound enhancement (ASE) function, in which an against-the-ear audio device having a speaker converts a digitally processed version of an input audio signal into amplified sound. The amplification may be in accordance with a stored hearing profile of the user. The audio system also has an acoustic noise cancellation (ANC) function that may be combined in various ways with the ASE function, and that may be responsive to voice activity detection. Other aspects are also described and claimed.

Headphone acoustic noise cancellation and speaker protection

An audio system has an ambient sound enhancement function, in which an against-the-ear audio device having a speaker converts a digitally processed version of an input audio signal into sound. The audio system also has an acoustic noise cancellation (ANC) function that may be combined in various ways with the sound enhancement function, and that may be responsive to voice activity detection. Other aspects are also described and claimed.

Ambient sound enhancement and acoustic noise cancellation based on context

A method for audio signal processing of microphone signals of a headphone. An audio signal from a first microphone of a headphone is filtered by an ANC system to produce a first filtered signal. Dynamic range control is performed upon the first filtered signal to produce a first dynamic range adjusted signal that drives a speaker of the headphone. Other aspects are also described and claimed.

Headphone acoustic noise cancellation and speaker protection or dynamic user experience processing

An audio system has an ambient sound enhancement function, in which an against-the-ear audio device having a speaker converts a digitally processed version of an input audio signal into sound. The input audio signal may be amplified where the amplification may be in accordance with a stored hearing profile of the user (personalized ambient sound enhancement.) The audio system also has an acoustic noise cancellation (ANC) function that may be combined in various ways with the sound enhancement function, and that may be responsive to voice activity detection. Other aspects are also described and claimed.

Ambient sound enhancement based on hearing profile and acoustic noise cancellation

A headphone has a driver, an internal microphone, an accelerometer, and an external microphone. An audio processor analyzes signals to detect wind noise. Gain of lower frequencies is reduced relative to higher frequencies, in a first filter that is operating on an audio signal from the external microphone in a feedforward path, responsive to detecting increased wind noise. A second filter in an audio signal feedback path may be adjusted to compensate for the gain change in the first filter that may mitigate occlusion effect. Outputs of the feedforward path in the feedback path are combined to produce an audio signal for the driver. The driver produces sound in the aural canal that has transparency with reduced wind noise, relative to sound external to the headphone. Other aspects are also described and claimed.

Headphone transparency, occlusion effect mitigation and wind noise detection

Method of wind and noise reduction for headphones starts by receiving acoustic signals from first external microphone included on the outside of earcup's housing. Acoustic signals are received from internal microphone included inside earcup's housing. ANC downlink corrector processes downlink signal to generate echo estimate of speaker signal. First summator removes echo estimate of speaker signal from acoustic signals from internal microphone to generate corrected internal microphone signal. Spectral combiner performs spectral mixing of corrected internal microphone signal with acoustic signals from first external microphone to generate mixed signal. Lower frequency portion of mixed signal includes corresponding lower frequency portion of corrected internal microphone signal, and higher frequency portion of mixed signal includes corresponding higher frequency portion of acoustic signals from first external microphone. Other embodiments are also described.

System and method of wind and noise reduction for a headphone

Some embodiments provide a multi-listener stereo image array which provides multiple separate stereo images of audio content to each of multiple listeners while mitigating interference of audio signals which provide separate stereo images to separate listeners. The array can include sensors which can monitor the environment and can identify relative positions of various listeners and can further control the audio signal patterns generated by the drivers of the array to propagate towards positions associated with particular listeners and be at least partially restricted from propagating towards positions associated with other listeners.

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Los Altos, CA, United States of America

Tom-Davy W Saux